What is a heat shrinkable cambric for wires - purpose and types

If the insulation of the wiring is broken, there are risks to human health and damage to property. Cylindrical wire sleeves slide over and cover cables to prevent breaks. The products are a piece of pipe and can withstand a voltage of 1000 V.

What are cambrics used for in electrical

The purpose of the tube is to isolate the electrical network, since the connection must be closed by welding, bolts, soldering, sleeves or terminal lugs. The cambric is put on the product, then the edges are closed with electrical tape. The free edge is heated and pressed down with pliers.

Thermocambric, in addition to its direct purpose, is used in such cases:

• restoration of the insulating layer of wiring with direct and alternating current;
• contact marking - other colors are clearly visible on the white tube;
• providing cable protection against breaks or damage;
• masking of connection points when installing electrical wiring;
• additional insulation of substation sections;
• preventing the edges of the printed circuit board from contacting each other.

Anglers use cambric to secure floats and hooks or even as bait.

Heat shrinkable tubing or PVC insulator

For the production of products, PVC or a special heat-shrinkable material is used.

Heat shrink tubing

They have several advantages:

• operation in a wide range of operating temperatures;
• less harmful emissions from melting or burning;
• long time of use;
• lack of exposure to aggressive environments.

The special inner lining of heat-shrinkable tubes remains airtight and adheres well when heated.

PVC cambric

There are 2 types of products:

• From a tube with a circular cross section. The cross-sections on the wires are not fixed, have a narrow temperature range and are only suitable for horizontal marking.
• Made of oval crimped tube. The profile consumable is attached to the cable due to the friction of the cable against the inner part, easily displaced. There should be space around the marked wiring.

The reusable consumables are different:

• high-quality electrical insulation;
• the ability to withstand stretching and mechanical stress;
• the possibility of repeated use;
• lack of expansion in length and width when heated;
• inexpensive cost.

Heat-shrinkable or PVC cambric in electrics should be used depending on the situation. To protect against short circuits of nearby components, heat shrink is suitable. During the heating process, open joints are crimped. The diameter of the PVC options is selected exclusively for the wire cross-section.

Types of cambric

The properties of insulators depend on the electrical insulating raw materials required for their manufacture.

Brief classification

By the type of application and composition, consumables are:

• Heat-resistant - multi-colored PVC tubes of different diameters to hide multi-core wiring.
• Temperature-dependent - made on the basis of cotton fabric, fiberglass and resin.The diameters and dimensions are the same. They are sealed by melting.

Thermocambrics, in turn, are subdivided into several categories:

• high-voltage - due to high resistance, they are used in conditions of high voltage;
• fluorescent - they are installed in rooms with poor illumination, since there are backlit particles in the composition;
• corrugated - textured surface allows you to use the product to prevent slipping;
• teflon - not subject to fire, aggressive and chemical environment;
• fiberglass - the main layer is covered with silicone varnish, which ensures the use in the assembly of automatic shields, ovens with induction burners;
• cotton - the fabric is impregnated with resin, which ensures its strength, resistance to deformation and good insulating properties.

Fiberglass cambric can be used in the process of connecting heating equipment.

Features of shrink cambric

Shrinkable consumables are made from polyethylene or other polymers. During the heating process, the product becomes 2 times smaller, so it is easy to choose it for wires with different cross-sections. The optimal shrinkage ratio for the cross section is 1: 2, 1: 3 and 1: 4.

As auxiliary means of insulation, various terminals and connections are used, the contours of which will repeat the heat shrinkage.

The stretch of the insulators is 1.5-2 times more than the initial, but during operation it is important to check the surface for rupture. Many colors of heat shrink provide opportunities for marking, dividing wires into groups.

The disadvantage of heat shrink tubes is a low melting point. At +200 degrees, they spread out.

Main advantages of using

Camshafts are universal consumables for all types of connections, insulation of exposed cable or wiring. Its operational advantages include:

• demand due to inexpensive cost and convenience of work;
• versatility of use - for installation on live sections, it is enough to choose the right diameter;
• long operating time with correct and uniform heating;
• reusability - the diameter from the old flap is used in another place;
• marking of conductors and restoration of damaged or erased markers;
• multifunctionality - various diameters of the tube are suitable for bundling cables, installing telephone-signal lines with low voltage.

Light cambric is best for wire marking.

Heat Resistant Fiberglass Cambric

The cross-sections have a fiberglass main layer and the surface is impregnated with silicone varnish. This manufacturing technology improves electrical performance and provides resistance.

The heat-resistant type insulator is practically not used for the arrangement of power grids. It is suitable for assembling induction cookers, dryers, automatic cabinets and heaters. The purpose of the fiberglass cambric is to protect the joints from damage when exposed to high temperatures.

Material specifications

The high temperature consumable is different:

• the ability to withstand a short maximum temperature of up to +400 degrees;
• long-term use in the temperature range from -60 to +350 degrees;
• dielectric density from 800 to 1200 V;
• inner diameter 3-150 mm;
• tolerance +/- 25 mm;
• nominal wall density 0.4 mm.

The material is absolutely non-combustible, has excellent strength and thermal conductivity, does not transmit current. Available with white or black casing.

It is more difficult to work with a heat-resistant cambric than with a heat-shrinkable one, because the outer walls are 2.5-3 mm thick.

Areas of use

A heat-resistant tube is chosen for such cases:

• organization of wiring protection with connected cartridge and clamp heating elements;
• cable insulation of household boilers or other equipment (iron, hair dryer, soldering iron);
• protection of connections of electrothermal equipment - drying chambers, tiles;
• hiding connections of cables and wires with heat-resistant properties.

Heat-resistant fiberglass cambric, designed for wires, does not change structure when exposed to cold.

Criterias of choice

When buying cambric, you should pay attention to several parameters:

• Internal diameter. The optimal size is from 1.5 to 2 core diameters. Manufacturers mark this value before shrinkage (fraction numerator) and after shrinkage (fraction denominator).
• Contraction range of the polymer layer. The allowed parameter is from 1.5 to 2 times.
• Reinforcement. Fiberglass models are hard, while cotton models allow you to fix the wire in a certain position.
• Resistant to hazardous reactions. Antiprene tubes are durable, flame resistant.
• Color. Dense multicolored or transparent thermotubes are available for sale.
• Length. The cambric is sold in lengths or in cable bundles.

Dimensions are in inches and centimeters.

How to use cambric

Under ideal working conditions, cambric shrinks in several ways.

Building hair dryer

The device produces a stream of hot air (200-300 degrees), which heats the thermotube. For precise direction of the jet, you can use a special nozzle. The compound will cool down and become solid after 30-40 seconds.

Soldering iron

The heating element is used as an alternative to a hair dryer. For shrinkage of the diameter, it is required to walk along its surface with the soldering iron casing. You cannot work with a sting:

• carbon deposits will remain on the surface;
• the sting will get dirty;
• cambric will melt at a temperature of more than 300 degrees.

No solder is used to shrink the heat pipe.

Sources of fire

Matches or a lighter are used as follows:

1. The flame burns at a distance of 2-3 cm from the cambric to avoid damage.
2. With quick and short movements, they pass from all sides, controlling the uniformity of the tightening.
3. The flame of the turbo lighter is directed so that only a stream of hot air hits the tube.

The disadvantage of this method is the trail of burning on the cambric.

The use of heat-shrinkable and heat-resistant cambrics is possible when organizing electrical communications. The material is popular due to its inexpensive cost and ease of use. High resistance values ​​and flame retardancy ensure protection of connection areas and cables.